1. Technical Field
The present invention relates to high speed data links and Ethernets and, more particularly, to an auto-negotiation (AN) method for establishing a high speed link in a gigabit Ethernet using the 1000 Base-T standard and an apparatus thereof.
2. Description of the Related Art
In general, the Ethernet is a model of a network that is used in a communications network, such as a local area network (LAN) installed in a specific area. In other words, the Ethernet is a coaxial cable network adopted by the Institution of Electrical and Electronic Engineers (IEEE). As the speed of Ethernet increases, gigabit Ethernet is beginning to be widely used. Gigabit Ethernet is defined in the IEEE 802.3 standard. More particularly, the 1000 Base-T standard is one of the standard protocols using coaxial cable and defines the IEEE 802.3ab model. Among the functions of gigabit Ethernet, an auto-negotiation (hereinafter referred to as “AN”) function is necessary to link transmitting devices, i.e., a remote station and a local station. In other words, the AN function determines the transmission speed and operating mode between the remote and local stations before linking them, and lets them communicate with each other based on the determined results. The local station could determine the transmission speed and operating mode with a parallel detection function in 10/100 Mbps Ethernet even though it does not have the AN function. Here, the parallel detection function is that in which a device not using the AN function detects a normal transmission mode and converts a transmission mode to a normal mode automatically when a device not using the AN function and another device using the AN function are linked with each other. However, in the case of the 1000 Mbps Ethernet, the AN function necessarily determines the transmission speed and the operating mode between transmitting devices. Also, master and slave functions are included in gigabit Ethernet. In other words, one of the linked devices serves as the master and the other serves as the slave. Thus, gigabit Ethernet requires the AN function.
FIG. 1 is a flow diagram illustrating the transmission process of a conventional AN method in high speed Ethernet using the 1000 Base-T standard. Referring to FIG. 1, five page transmission steps are performed between transmitting devices to carry out the conventional AN function under the 1000 Base-T standard. After an initial reset (step 100), a transmitting device transmits a base page (hereinafter referred to as “BP”), which denotes a transmission standard and a basic transmission speed (step 110). Next, a message page (hereinafter referred to as “MP”) is transmitted to indicate the possibility of transmission at a speed of 1000 Mbps and two unformatted message pages (hereinafter referred to as “UP”) to be transmitted (step 120). Here, the message expressed in the MP generally shows a predetermined number, e.g., “8”. In other words, the message “8” shows that two UPs will be transmitted later. The transmitting device transmits first and second unformatted message pages UP1 and UP2 (steps 130 and 140) and then a null page (hereinafter referred to as “NP”) (step 150). Here, the UP1 includes transmission speed and mode, device type, and duplex mode. The UP2 includes random seed values. Through these steps, the link is established between two transmitting devices and the AN ends (step 160).
FIG. 2 is a flow diagram illustrating the receiving process of the conventional AN method in high speed Ethernet using the 1000 Base-T standard. Referring to FIG. 2, as in the transmission steps, in the receiving steps (steps 210 through 260) which follow an idle step (step 200), a link is established and the AN ends (step 260) after five pages of information are received (steps 210 through 250). Also, the MP in the receiving steps shows the same integer “8” as that of the MP in the transmission steps.
As shown in FIGS. 1 and 2, under the current IEEE 802.3ab standard, the normal link is established between transmitting devices after the UP1, the UP2, and the NP are transmitted if transmission is possible at a speed of 1000 Mbps based on the analysis of transmitted and received MP. However, if the port types of the transmitting devices are different from each other, then the transmission mode and speed are determined only by the UP1. In other words, in the prior art, the AN is completed only when the UP2 is transmitted although the UP2 is not necessary. Thus, the time required for establishing an AN link can increase due to the transmission of the UP2.